The role of polygenic adaptation and genetic redundancy in gene expression evolution

Title (eng)
The role of polygenic adaptation and genetic redundancy in gene expression evolution
Author
Wei-Yun Lai
Description (eng)
PhD thesis - University of Veterinary Medicine Vienna - 2022 The full text is only available to university members. Please log in!
Abstract (eng)
Many traits of interest are highly heritable and controlled by many numbers of loci. Understanding the genetic basis of complex traits and their evolution in response to changing environments (i.e., polygenic adaptation) have been studied for decades. Polygenic adaptation can produce a heterogeneous selection signature at genomic/gene level as alternative paths could be taken during adaptive processes and transmitted into similar output at high-level phenotypes. Although this phenomenon is empirically documented, the molecular basis of the genetic redundancy is not yet understood. To fill this gap, in this thesis, we first quantified the heterogeneity of the evolutionary transcriptomic and metabolomic response in 10 Drosophila simulans populations which evolved parallel high level phenotypic changes in a novel temperature environment but used different allelic combinations of alternative loci. We showed that the metabolome evolved more parallel than the transcriptome, confirming a hierarchical organization of molecular phenotypes. Different sets of genes responded in each evolved population but led to the enrichment of similar biological functions and a consistent metabolic profile. Given the variation in gene expression parallelism across genes, we further investigated the effect of pleiotropy on the evolutionary parallelism of gene expression (i.e., how similar is the response the same genes to selection in multiple populations adapting to the same/similar ecological niche(s)). Lastly, together with the computer simulation, we evaluated whether the presence/absence of the changes in phenotypic variance during selection on mean could provide insights into the genetic basis of adaptation for gene expression phenotypes. This thesis advances the knowledge on polygenic adaptation on the molecular levels.
Description (deu)
PhD Arbeit - Veterinärmedizinische Universität Wien - 2022 Aus rechtlichen Gründen sind nicht alle Teile dieser Arbeit frei zugänglich. Der Zugriff auf den elektronischen Volltext ist auf Angehörige der Veterinärmedizinischen Universität Wien beschränkt. Bitte einloggen!
Type (eng)
Dissertation
Language
[eng]
Persistent identifier
https://phaidra.vetmeduni.ac.at/o:4559
AC number
AC17640165
DOI
10.34876/FXJT-1N50
Number of pages
130
Date issued
2022
License
All rights reserved